The present invention relates to improvement in circular saws, and more particularly to those saws of a carbide-tipped type.
More particularly, the present invention relates to an improved design for the raking surfaces of circular saws having concave teeth.
The prior art has seen a wide variety of circular cutting saws and, more specifically, those saws provided with cutting teeth having a concave surface. Saw blades fitted with such concave raking surfaces have been highly regarded for their superior cutting characteristics. However, the use of such blade has been limited because of the expense and difficulty which has been encountered in attempts to adequately effectuate the regrinding of the teeth of such saws. This problem is due, in large measure, to the rapid consumption of the small diameter grinding wheels which must be utilized in the regrinding of such concave teeth. This situation is shown in FIGS. 1A (a typical prior art concave surface) and FIG. 1B which indicates, at diameter D1, the limited size which a grinding wheel utilized in the prior art area must, of necessity, possess.
As a consequence of the small diameter D1 possessed by grinding wheels utilized in association with the reconstitution of prior art concave surfaces, it can be appreciated that a relatively long period of time is required in order to effectuate the grinding of each tooth. In addition, it can be appreciated that, as an inevitable consequence of the shape of any concave tooth having a uniform radius, the size of the gullet 18 (see FIG. 1B) associated with each tooth will, of physical necessity, have a minimum radius. As a result of such a minimum radius, the total number of teeth (occasionally referred to as tips) which can be placed upon a saw of given circumference has, in the prior art, been limited.
A further shortcoming attendant in the prior art has been the phenomenon of undue chipping of the materials being cut. This is a particularly undesirable characteristic when the material being cut is one having a special susceptibility to chipping, as for example, in the case of flakeboard coated on both surfaces with a hard, brittle decorative melamine skin.
In light of the above, it is the intent of the present invention to provide a concave cutting surface having a configuration which will permit the use of significantly larger diameter grinding wheels, thereby significantly reducing grinding time, significantly increasing the life of the grinding wheels, and permitting the design and construction of saw blades having concave teeth, without regard to the number of teeth per blade.